Preventing corrosion of brass

[EDG]

This PDF is a copper industry paper about the use of benzotriazole to prevent the corrosion of brass.
Before I bought a tumbler about 1970, I cleaned a lot of cases with the vinegar and salt solution.
No matter how well I rinsed the brass it would always turn dark over time. Vinegar helped remove corrosion but it seemed to leave the cases unprotected after it stripped the corrosion off the cases.
Birchwood Casey Case Cleaner is an acid based cleaner that I have used for a long time to clean cases. It will also rehabilitate corroded brass. Cases treated and not tumbled will retain the acid cleaned finish for 5 years or more without tarnish. Reviewing the BC MSDS revealed the benzothiazole ingredient. From the paper it appears that you can use a solution of .25% benzothiazole in water at 60degrees C or 140F for 2 minutes to provide tarnish and corrosion protection for your brass.

http://www.copper.org/publications/pub_list/pdf/a1349.pdf

[myg30]

Might be good idea for the guys that wet tumble and use this in their rinse. Brass that I tumbled clean in walnut media treated with nufinish and mineral spirits then sealed in zip lok type baggies
and sitting for years seem to be looking good so far.
The bags that were not sealed well have tarnished some but I know their clean !

In this case the non shinny brass on the floor at the range is mine !

Good find EDG ! Now to see what products we have at home include Benzotriazol in it !!

Mike

[Iron Whittler]

Where can this stuff be purchased? I am going to try liquid/ss pins tumbling to clean my brass. Iron Whittler

[EDG]

The chemical name is 1,2,3 benzotriazole or benzotriazole CAS 95 14 7.
It is pretty expensive but it is used at very low concentrations so a little goes a long way.

I have been researching the costs it seems to be available at photography chemical supply houses and at chemical suppliers. You will want commercial grade for the lowest price. Technical grade or photography grades are more expensive and reagent grade is ridiculous.


At this link it is $4.95 for 10 grams or $16.95 for 100 grams.



http://stores.photoformulary.com/benzotriazole/